b461a6ab63
Current implementation of short-circuting is just plain wrong as it uses `last` or `before-last` labels which meaning depend on context. It doesn't even handle simple assignements like `a := x == 1 && y == 2`. This commit makes all jumps in such conditions local and adds tests. Closes #699, #700.
1257 lines
32 KiB
Go
1257 lines
32 KiB
Go
package compiler
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"go/ast"
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"go/constant"
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"go/token"
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"go/types"
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"math"
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"sort"
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"strconv"
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"strings"
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"github.com/CityOfZion/neo-go/pkg/encoding/address"
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"github.com/CityOfZion/neo-go/pkg/io"
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"github.com/CityOfZion/neo-go/pkg/vm"
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"github.com/CityOfZion/neo-go/pkg/vm/emit"
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"github.com/CityOfZion/neo-go/pkg/vm/opcode"
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)
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// The identifier of the entry function. Default set to Main.
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const mainIdent = "Main"
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type codegen struct {
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// Information about the program with all its dependencies.
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buildInfo *buildInfo
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// prog holds the output buffer.
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prog *io.BufBinWriter
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// Type information.
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typeInfo *types.Info
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// A mapping of func identifiers with their scope.
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funcs map[string]*funcScope
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// Current funcScope being converted.
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scope *funcScope
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// A mapping from label's names to their ids.
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labels map[labelWithType]uint16
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// A label for the for-loop being currently visited.
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currentFor string
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// A label for the switch statement being visited.
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currentSwitch string
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// A label to be used in the next statement.
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nextLabel string
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// Label table for recording jump destinations.
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l []int
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}
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type labelOffsetType byte
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const (
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labelStart labelOffsetType = iota // labelStart is a default label type
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labelEnd // labelEnd is a type for labels that are targets for break
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labelPost // labelPost is a type for labels that are targets for continue
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)
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type labelWithType struct {
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name string
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typ labelOffsetType
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}
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// newLabel creates a new label to jump to
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func (c *codegen) newLabel() (l uint16) {
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li := len(c.l)
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if li > math.MaxUint16 {
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c.prog.Err = errors.New("label number is too big")
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return
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}
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l = uint16(li)
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c.l = append(c.l, -1)
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return
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}
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// newNamedLabel creates a new label with a specified name.
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func (c *codegen) newNamedLabel(typ labelOffsetType, name string) (l uint16) {
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l = c.newLabel()
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lt := labelWithType{name: name, typ: typ}
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c.labels[lt] = l
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return
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}
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func (c *codegen) setLabel(l uint16) {
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c.l[l] = c.pc() + 1
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}
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// pc returns the program offset off the last instruction.
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func (c *codegen) pc() int {
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return c.prog.Len() - 1
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}
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func (c *codegen) emitLoadConst(t types.TypeAndValue) {
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if c.prog.Err != nil {
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return
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}
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switch typ := t.Type.Underlying().(type) {
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case *types.Basic:
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c.convertBasicType(t, typ)
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default:
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c.prog.Err = fmt.Errorf("compiler doesn't know how to convert this constant: %v", t)
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return
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}
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}
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func (c *codegen) convertBasicType(t types.TypeAndValue, typ *types.Basic) {
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switch typ.Kind() {
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case types.Int, types.UntypedInt, types.Uint:
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val, _ := constant.Int64Val(t.Value)
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emit.Int(c.prog.BinWriter, val)
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case types.String, types.UntypedString:
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val := constant.StringVal(t.Value)
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emit.String(c.prog.BinWriter, val)
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case types.Bool, types.UntypedBool:
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val := constant.BoolVal(t.Value)
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emit.Bool(c.prog.BinWriter, val)
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case types.Byte:
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val, _ := constant.Int64Val(t.Value)
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b := byte(val)
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emit.Bytes(c.prog.BinWriter, []byte{b})
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default:
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c.prog.Err = fmt.Errorf("compiler doesn't know how to convert this basic type: %v", t)
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return
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}
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}
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func (c *codegen) emitLoadLocal(name string) {
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pos := c.scope.loadLocal(name)
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if pos < 0 {
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c.prog.Err = fmt.Errorf("cannot load local variable with position: %d", pos)
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return
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}
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c.emitLoadLocalPos(pos)
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}
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func (c *codegen) emitLoadLocalPos(pos int) {
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emit.Opcode(c.prog.BinWriter, opcode.DUPFROMALTSTACK)
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emit.Int(c.prog.BinWriter, int64(pos))
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emit.Opcode(c.prog.BinWriter, opcode.PICKITEM)
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}
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func (c *codegen) emitStoreLocal(pos int) {
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emit.Opcode(c.prog.BinWriter, opcode.DUPFROMALTSTACK)
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if pos < 0 {
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c.prog.Err = fmt.Errorf("invalid position to store local: %d", pos)
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return
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}
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emit.Int(c.prog.BinWriter, int64(pos))
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emit.Opcode(c.prog.BinWriter, opcode.ROT)
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emit.Opcode(c.prog.BinWriter, opcode.SETITEM)
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}
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func (c *codegen) emitLoadField(i int) {
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emit.Int(c.prog.BinWriter, int64(i))
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emit.Opcode(c.prog.BinWriter, opcode.PICKITEM)
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}
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func (c *codegen) emitStoreStructField(i int) {
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emit.Int(c.prog.BinWriter, int64(i))
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emit.Opcode(c.prog.BinWriter, opcode.ROT)
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emit.Opcode(c.prog.BinWriter, opcode.SETITEM)
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}
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// convertGlobals traverses the AST and only converts global declarations.
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// If we call this in convertFuncDecl then it will load all global variables
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// into the scope of the function.
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func (c *codegen) convertGlobals(f ast.Node) {
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ast.Inspect(f, func(node ast.Node) bool {
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switch n := node.(type) {
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case *ast.FuncDecl:
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return false
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case *ast.GenDecl:
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// constants are loaded directly so there is no need
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// to store them as a local variables
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if n.Tok != token.CONST {
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ast.Walk(c, n)
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}
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}
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return true
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})
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}
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func (c *codegen) convertFuncDecl(file ast.Node, decl *ast.FuncDecl) {
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var (
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f *funcScope
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ok bool
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)
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f, ok = c.funcs[decl.Name.Name]
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if ok {
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// If this function is a syscall we will not convert it to bytecode.
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if isSyscall(f) {
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return
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}
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c.setLabel(f.label)
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} else {
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f = c.newFunc(decl)
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}
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c.scope = f
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ast.Inspect(decl, c.scope.analyzeVoidCalls) // @OPTIMIZE
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// All globals copied into the scope of the function need to be added
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// to the stack size of the function.
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emit.Int(c.prog.BinWriter, f.stackSize()+countGlobals(file))
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emit.Opcode(c.prog.BinWriter, opcode.NEWARRAY)
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emit.Opcode(c.prog.BinWriter, opcode.TOALTSTACK)
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// We need to handle methods, which in Go, is just syntactic sugar.
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// The method receiver will be passed in as first argument.
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// We check if this declaration has a receiver and load it into scope.
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//
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// FIXME: For now we will hard cast this to a struct. We can later fine tune this
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// to support other types.
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if decl.Recv != nil {
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for _, arg := range decl.Recv.List {
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ident := arg.Names[0]
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// Currently only method receives for struct types is supported.
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_, ok := c.typeInfo.Defs[ident].Type().Underlying().(*types.Struct)
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if !ok {
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c.prog.Err = fmt.Errorf("method receives for non-struct types is not yet supported")
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return
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}
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l := c.scope.newLocal(ident.Name)
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c.emitStoreLocal(l)
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}
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}
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// Load the arguments in scope.
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for _, arg := range decl.Type.Params.List {
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name := arg.Names[0].Name // for now.
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l := c.scope.newLocal(name)
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c.emitStoreLocal(l)
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}
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// Load in all the global variables in to the scope of the function.
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// This is not necessary for syscalls.
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if !isSyscall(f) {
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c.convertGlobals(file)
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}
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ast.Walk(c, decl.Body)
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// If this function returns the void (no return stmt) we will cleanup its junk on the stack.
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if !hasReturnStmt(decl) {
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emit.Opcode(c.prog.BinWriter, opcode.FROMALTSTACK)
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emit.Opcode(c.prog.BinWriter, opcode.DROP)
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emit.Opcode(c.prog.BinWriter, opcode.RET)
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}
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}
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func (c *codegen) Visit(node ast.Node) ast.Visitor {
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if c.prog.Err != nil {
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return nil
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}
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switch n := node.(type) {
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// General declarations.
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// var (
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// x = 2
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// )
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case *ast.GenDecl:
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for _, spec := range n.Specs {
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switch t := spec.(type) {
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case *ast.ValueSpec:
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for i, val := range t.Values {
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ast.Walk(c, val)
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l := c.scope.newLocal(t.Names[i].Name)
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c.emitStoreLocal(l)
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}
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}
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}
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return nil
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case *ast.AssignStmt:
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multiRet := len(n.Rhs) != len(n.Lhs)
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for i := 0; i < len(n.Lhs); i++ {
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switch t := n.Lhs[i].(type) {
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case *ast.Ident:
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switch n.Tok {
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case token.ADD_ASSIGN, token.SUB_ASSIGN, token.MUL_ASSIGN, token.QUO_ASSIGN, token.REM_ASSIGN:
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c.emitLoadLocal(t.Name)
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ast.Walk(c, n.Rhs[0]) // can only add assign to 1 expr on the RHS
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c.convertToken(n.Tok)
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l := c.scope.loadLocal(t.Name)
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c.emitStoreLocal(l)
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default:
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if i == 0 || !multiRet {
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ast.Walk(c, n.Rhs[i])
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}
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if t.Name == "_" {
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emit.Opcode(c.prog.BinWriter, opcode.DROP)
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} else {
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l := c.scope.loadLocal(t.Name)
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c.emitStoreLocal(l)
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}
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}
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case *ast.SelectorExpr:
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switch expr := t.X.(type) {
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case *ast.Ident:
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ast.Walk(c, n.Rhs[i])
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typ := c.typeInfo.ObjectOf(expr).Type().Underlying()
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if strct, ok := typ.(*types.Struct); ok {
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c.emitLoadLocal(expr.Name) // load the struct
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i := indexOfStruct(strct, t.Sel.Name) // get the index of the field
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c.emitStoreStructField(i) // store the field
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}
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default:
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c.prog.Err = fmt.Errorf("nested selector assigns not supported yet")
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return nil
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}
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// Assignments to index expressions.
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// slice[0] = 10
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case *ast.IndexExpr:
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ast.Walk(c, n.Rhs[i])
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name := t.X.(*ast.Ident).Name
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c.emitLoadLocal(name)
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switch ind := t.Index.(type) {
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case *ast.BasicLit:
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indexStr := ind.Value
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index, err := strconv.Atoi(indexStr)
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if err != nil {
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c.prog.Err = fmt.Errorf("failed to convert slice index to integer")
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return nil
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}
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c.emitStoreStructField(index)
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case *ast.Ident:
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c.emitLoadLocal(ind.Name)
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emit.Opcode(c.prog.BinWriter, opcode.ROT)
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emit.Opcode(c.prog.BinWriter, opcode.SETITEM)
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default:
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c.prog.Err = fmt.Errorf("unsupported index expression")
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return nil
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}
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}
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}
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return nil
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case *ast.SliceExpr:
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name := n.X.(*ast.Ident).Name
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c.emitLoadLocal(name)
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if n.Low != nil {
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ast.Walk(c, n.Low)
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} else {
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emit.Opcode(c.prog.BinWriter, opcode.PUSH0)
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}
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if n.High != nil {
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ast.Walk(c, n.High)
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} else {
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emit.Opcode(c.prog.BinWriter, opcode.OVER)
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emit.Opcode(c.prog.BinWriter, opcode.ARRAYSIZE)
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}
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emit.Opcode(c.prog.BinWriter, opcode.OVER)
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emit.Opcode(c.prog.BinWriter, opcode.SUB)
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emit.Opcode(c.prog.BinWriter, opcode.SUBSTR)
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return nil
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case *ast.ReturnStmt:
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l := c.newLabel()
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c.setLabel(l)
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// first result should be on top of the stack
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for i := len(n.Results) - 1; i >= 0; i-- {
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ast.Walk(c, n.Results[i])
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}
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emit.Opcode(c.prog.BinWriter, opcode.FROMALTSTACK)
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emit.Opcode(c.prog.BinWriter, opcode.DROP) // Cleanup the stack.
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emit.Opcode(c.prog.BinWriter, opcode.RET)
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return nil
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case *ast.IfStmt:
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lIf := c.newLabel()
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lElse := c.newLabel()
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lElseEnd := c.newLabel()
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if n.Cond != nil {
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ast.Walk(c, n.Cond)
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emit.Jmp(c.prog.BinWriter, opcode.JMPIFNOT, lElse)
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}
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c.setLabel(lIf)
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ast.Walk(c, n.Body)
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if n.Else != nil {
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emit.Jmp(c.prog.BinWriter, opcode.JMP, lElseEnd)
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}
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c.setLabel(lElse)
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if n.Else != nil {
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ast.Walk(c, n.Else)
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}
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c.setLabel(lElseEnd)
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return nil
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case *ast.SwitchStmt:
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// fallthrough is not supported
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ast.Walk(c, n.Tag)
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eqOpcode := c.getEqualityOpcode(n.Tag)
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switchEnd, label := c.generateLabel(labelEnd)
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lastSwitch := c.currentSwitch
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c.currentSwitch = label
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for i := range n.Body.List {
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lEnd := c.newLabel()
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lStart := c.newLabel()
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cc := n.Body.List[i].(*ast.CaseClause)
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if l := len(cc.List); l != 0 { // if not `default`
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for j := range cc.List {
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emit.Opcode(c.prog.BinWriter, opcode.DUP)
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ast.Walk(c, cc.List[j])
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emit.Opcode(c.prog.BinWriter, eqOpcode)
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if j == l-1 {
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emit.Jmp(c.prog.BinWriter, opcode.JMPIFNOT, lEnd)
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} else {
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emit.Jmp(c.prog.BinWriter, opcode.JMPIF, lStart)
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}
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}
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}
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c.setLabel(lStart)
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for _, stmt := range cc.Body {
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ast.Walk(c, stmt)
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}
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emit.Jmp(c.prog.BinWriter, opcode.JMP, switchEnd)
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c.setLabel(lEnd)
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}
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c.setLabel(switchEnd)
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emit.Opcode(c.prog.BinWriter, opcode.DROP)
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c.currentSwitch = lastSwitch
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return nil
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|
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case *ast.BasicLit:
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c.emitLoadConst(c.typeInfo.Types[n])
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return nil
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|
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case *ast.Ident:
|
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if isIdentBool(n) {
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value, err := makeBoolFromIdent(n, c.typeInfo)
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if err != nil {
|
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c.prog.Err = err
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return nil
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}
|
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c.emitLoadConst(value)
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} else if tv := c.typeInfo.Types[n]; tv.Value != nil {
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c.emitLoadConst(tv)
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} else {
|
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c.emitLoadLocal(n.Name)
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}
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return nil
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|
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case *ast.CompositeLit:
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var typ types.Type
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switch t := n.Type.(type) {
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case *ast.Ident:
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typ = c.typeInfo.ObjectOf(t).Type().Underlying()
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case *ast.SelectorExpr:
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typ = c.typeInfo.ObjectOf(t.Sel).Type().Underlying()
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case *ast.MapType:
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typ = c.typeInfo.TypeOf(t)
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default:
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ln := len(n.Elts)
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|
// ByteArrays needs a different approach than normal arrays.
|
|
if isByteArray(n, c.typeInfo) {
|
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c.convertByteArray(n)
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return nil
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}
|
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for i := ln - 1; i >= 0; i-- {
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ast.Walk(c, n.Elts[i])
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}
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emit.Int(c.prog.BinWriter, int64(ln))
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emit.Opcode(c.prog.BinWriter, opcode.PACK)
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return nil
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}
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|
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switch typ.(type) {
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case *types.Struct:
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c.convertStruct(n)
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case *types.Map:
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c.convertMap(n)
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}
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return nil
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|
|
case *ast.BinaryExpr:
|
|
switch n.Op {
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case token.LAND:
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next := c.newLabel()
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end := c.newLabel()
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ast.Walk(c, n.X)
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emit.Jmp(c.prog.BinWriter, opcode.JMPIF, next)
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emit.Opcode(c.prog.BinWriter, opcode.PUSHF)
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emit.Jmp(c.prog.BinWriter, opcode.JMP, end)
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c.setLabel(next)
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ast.Walk(c, n.Y)
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c.setLabel(end)
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return nil
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|
|
case token.LOR:
|
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next := c.newLabel()
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end := c.newLabel()
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ast.Walk(c, n.X)
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMPIFNOT, next)
|
|
emit.Opcode(c.prog.BinWriter, opcode.PUSHT)
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMP, end)
|
|
c.setLabel(next)
|
|
ast.Walk(c, n.Y)
|
|
c.setLabel(end)
|
|
return nil
|
|
|
|
default:
|
|
// The AST package will try to resolve all basic literals for us.
|
|
// If the typeinfo.Value is not nil we know that the expr is resolved
|
|
// and needs no further action. e.g. x := 2 + 2 + 2 will be resolved to 6.
|
|
// NOTE: Constants will also be automatically resolved be the AST parser.
|
|
// example:
|
|
// const x = 10
|
|
// x + 2 will results into 12
|
|
tinfo := c.typeInfo.Types[n]
|
|
if tinfo.Value != nil {
|
|
c.emitLoadConst(tinfo)
|
|
return nil
|
|
}
|
|
|
|
ast.Walk(c, n.X)
|
|
ast.Walk(c, n.Y)
|
|
|
|
switch {
|
|
case n.Op == token.ADD:
|
|
// VM has separate opcodes for number and string concatenation
|
|
if isStringType(tinfo.Type) {
|
|
emit.Opcode(c.prog.BinWriter, opcode.CAT)
|
|
} else {
|
|
emit.Opcode(c.prog.BinWriter, opcode.ADD)
|
|
}
|
|
case n.Op == token.EQL:
|
|
// VM has separate opcodes for number and string equality
|
|
op := c.getEqualityOpcode(n.X)
|
|
emit.Opcode(c.prog.BinWriter, op)
|
|
case n.Op == token.NEQ:
|
|
// VM has separate opcodes for number and string equality
|
|
if isStringType(c.typeInfo.Types[n.X].Type) {
|
|
emit.Opcode(c.prog.BinWriter, opcode.EQUAL)
|
|
emit.Opcode(c.prog.BinWriter, opcode.NOT)
|
|
} else {
|
|
emit.Opcode(c.prog.BinWriter, opcode.NUMNOTEQUAL)
|
|
}
|
|
default:
|
|
c.convertToken(n.Op)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
case *ast.CallExpr:
|
|
var (
|
|
f *funcScope
|
|
ok bool
|
|
numArgs = len(n.Args)
|
|
isBuiltin = isBuiltin(n.Fun)
|
|
)
|
|
|
|
switch fun := n.Fun.(type) {
|
|
case *ast.Ident:
|
|
f, ok = c.funcs[fun.Name]
|
|
if !ok && !isBuiltin {
|
|
c.prog.Err = fmt.Errorf("could not resolve function %s", fun.Name)
|
|
return nil
|
|
}
|
|
case *ast.SelectorExpr:
|
|
// If this is a method call we need to walk the AST to load the struct locally.
|
|
// Otherwise this is a function call from a imported package and we can call it
|
|
// directly.
|
|
if c.typeInfo.Selections[fun] != nil {
|
|
ast.Walk(c, fun.X)
|
|
// Dont forget to add 1 extra argument when its a method.
|
|
numArgs++
|
|
}
|
|
|
|
f, ok = c.funcs[fun.Sel.Name]
|
|
// @FIXME this could cause runtime errors.
|
|
f.selector = fun.X.(*ast.Ident)
|
|
if !ok {
|
|
c.prog.Err = fmt.Errorf("could not resolve function %s", fun.Sel.Name)
|
|
return nil
|
|
}
|
|
case *ast.ArrayType:
|
|
// For now we will assume that there are only byte slice conversions.
|
|
// E.g. []byte("foobar") or []byte(scriptHash).
|
|
ast.Walk(c, n.Args[0])
|
|
return nil
|
|
}
|
|
|
|
args := transformArgs(n.Fun, n.Args)
|
|
|
|
// Handle the arguments
|
|
for _, arg := range args {
|
|
ast.Walk(c, arg)
|
|
}
|
|
// Do not swap for builtin functions.
|
|
if !isBuiltin {
|
|
c.emitReverse(numArgs)
|
|
}
|
|
|
|
// Check builtin first to avoid nil pointer on funcScope!
|
|
switch {
|
|
case isBuiltin:
|
|
// Use the ident to check, builtins are not in func scopes.
|
|
// We can be sure builtins are of type *ast.Ident.
|
|
c.convertBuiltin(n)
|
|
case isSyscall(f):
|
|
c.convertSyscall(f.selector.Name, f.name)
|
|
default:
|
|
emit.Call(c.prog.BinWriter, opcode.CALL, f.label)
|
|
}
|
|
|
|
return nil
|
|
|
|
case *ast.SelectorExpr:
|
|
switch t := n.X.(type) {
|
|
case *ast.Ident:
|
|
typ := c.typeInfo.ObjectOf(t).Type().Underlying()
|
|
if strct, ok := typ.(*types.Struct); ok {
|
|
c.emitLoadLocal(t.Name) // load the struct
|
|
i := indexOfStruct(strct, n.Sel.Name)
|
|
c.emitLoadField(i) // load the field
|
|
}
|
|
default:
|
|
c.prog.Err = fmt.Errorf("nested selectors not supported yet")
|
|
return nil
|
|
}
|
|
return nil
|
|
|
|
case *ast.UnaryExpr:
|
|
ast.Walk(c, n.X)
|
|
// From https://golang.org/ref/spec#Operators
|
|
// there can be only following unary operators
|
|
// "+" | "-" | "!" | "^" | "*" | "&" | "<-" .
|
|
// of which last three are not used in SC
|
|
switch n.Op {
|
|
case token.ADD:
|
|
// +10 == 10, no need to do anything in this case
|
|
case token.SUB:
|
|
emit.Opcode(c.prog.BinWriter, opcode.NEGATE)
|
|
case token.NOT:
|
|
emit.Opcode(c.prog.BinWriter, opcode.NOT)
|
|
case token.XOR:
|
|
emit.Opcode(c.prog.BinWriter, opcode.INVERT)
|
|
default:
|
|
c.prog.Err = fmt.Errorf("invalid unary operator: %s", n.Op)
|
|
return nil
|
|
}
|
|
return nil
|
|
|
|
case *ast.IncDecStmt:
|
|
ast.Walk(c, n.X)
|
|
c.convertToken(n.Tok)
|
|
|
|
// For now only identifiers are supported for (post) for stmts.
|
|
// for i := 0; i < 10; i++ {}
|
|
// Where the post stmt is ( i++ )
|
|
if ident, ok := n.X.(*ast.Ident); ok {
|
|
pos := c.scope.loadLocal(ident.Name)
|
|
c.emitStoreLocal(pos)
|
|
}
|
|
return nil
|
|
|
|
case *ast.IndexExpr:
|
|
// Walk the expression, this could be either an Ident or SelectorExpr.
|
|
// This will load local whatever X is.
|
|
ast.Walk(c, n.X)
|
|
|
|
switch n.Index.(type) {
|
|
case *ast.BasicLit:
|
|
t := c.typeInfo.Types[n.Index]
|
|
switch typ := t.Type.Underlying().(type) {
|
|
case *types.Basic:
|
|
c.convertBasicType(t, typ)
|
|
default:
|
|
c.prog.Err = fmt.Errorf("compiler can't use following type as an index: %T", typ)
|
|
return nil
|
|
}
|
|
default:
|
|
ast.Walk(c, n.Index)
|
|
}
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.PICKITEM) // just pickitem here
|
|
|
|
return nil
|
|
|
|
case *ast.BranchStmt:
|
|
var label string
|
|
if n.Label != nil {
|
|
label = n.Label.Name
|
|
} else if n.Tok == token.BREAK {
|
|
label = c.currentSwitch
|
|
} else if n.Tok == token.CONTINUE {
|
|
label = c.currentFor
|
|
}
|
|
|
|
switch n.Tok {
|
|
case token.BREAK:
|
|
end := c.getLabelOffset(labelEnd, label)
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMP, end)
|
|
case token.CONTINUE:
|
|
post := c.getLabelOffset(labelPost, label)
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMP, post)
|
|
}
|
|
|
|
return nil
|
|
|
|
case *ast.LabeledStmt:
|
|
c.nextLabel = n.Label.Name
|
|
|
|
ast.Walk(c, n.Stmt)
|
|
|
|
return nil
|
|
|
|
case *ast.ForStmt:
|
|
fstart, label := c.generateLabel(labelStart)
|
|
fend := c.newNamedLabel(labelEnd, label)
|
|
fpost := c.newNamedLabel(labelPost, label)
|
|
|
|
lastLabel := c.currentFor
|
|
lastSwitch := c.currentSwitch
|
|
c.currentFor = label
|
|
c.currentSwitch = label
|
|
|
|
// Walk the initializer and condition.
|
|
if n.Init != nil {
|
|
ast.Walk(c, n.Init)
|
|
}
|
|
|
|
// Set label and walk the condition.
|
|
c.setLabel(fstart)
|
|
ast.Walk(c, n.Cond)
|
|
|
|
// Jump if the condition is false
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMPIFNOT, fend)
|
|
|
|
// Walk body followed by the iterator (post stmt).
|
|
ast.Walk(c, n.Body)
|
|
c.setLabel(fpost)
|
|
if n.Post != nil {
|
|
ast.Walk(c, n.Post)
|
|
}
|
|
|
|
// Jump back to condition.
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMP, fstart)
|
|
c.setLabel(fend)
|
|
|
|
c.currentFor = lastLabel
|
|
c.currentSwitch = lastSwitch
|
|
|
|
return nil
|
|
|
|
case *ast.RangeStmt:
|
|
// currently only simple for-range loops are supported
|
|
// for i := range ...
|
|
if n.Value != nil {
|
|
c.prog.Err = errors.New("range loops with value variable are not supported")
|
|
return nil
|
|
}
|
|
|
|
start, label := c.generateLabel(labelStart)
|
|
end := c.newNamedLabel(labelEnd, label)
|
|
post := c.newNamedLabel(labelPost, label)
|
|
|
|
lastFor := c.currentFor
|
|
lastSwitch := c.currentSwitch
|
|
c.currentFor = label
|
|
c.currentSwitch = label
|
|
|
|
ast.Walk(c, n.X)
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.ARRAYSIZE)
|
|
emit.Opcode(c.prog.BinWriter, opcode.PUSH0)
|
|
|
|
c.setLabel(start)
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.OVER)
|
|
emit.Opcode(c.prog.BinWriter, opcode.OVER)
|
|
emit.Opcode(c.prog.BinWriter, opcode.LTE) // finish if len <= i
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMPIF, end)
|
|
|
|
if n.Key != nil {
|
|
emit.Opcode(c.prog.BinWriter, opcode.DUP)
|
|
|
|
pos := c.scope.loadLocal(n.Key.(*ast.Ident).Name)
|
|
c.emitStoreLocal(pos)
|
|
}
|
|
|
|
ast.Walk(c, n.Body)
|
|
|
|
c.setLabel(post)
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.INC)
|
|
emit.Jmp(c.prog.BinWriter, opcode.JMP, start)
|
|
|
|
c.setLabel(end)
|
|
|
|
c.currentFor = lastFor
|
|
c.currentSwitch = lastSwitch
|
|
|
|
return nil
|
|
|
|
// We dont really care about assertions for the core logic.
|
|
// The only thing we need is to please the compiler type checking.
|
|
// For this to work properly, we only need to walk the expression
|
|
// not the assertion type.
|
|
case *ast.TypeAssertExpr:
|
|
ast.Walk(c, n.X)
|
|
return nil
|
|
}
|
|
return c
|
|
}
|
|
|
|
// emitReverse reverses top num items of the stack.
|
|
func (c *codegen) emitReverse(num int) {
|
|
switch num {
|
|
case 2:
|
|
emit.Opcode(c.prog.BinWriter, opcode.SWAP)
|
|
case 3:
|
|
emit.Int(c.prog.BinWriter, 2)
|
|
emit.Opcode(c.prog.BinWriter, opcode.XSWAP)
|
|
default:
|
|
for i := 1; i < num; i++ {
|
|
emit.Int(c.prog.BinWriter, int64(i))
|
|
emit.Opcode(c.prog.BinWriter, opcode.ROLL)
|
|
}
|
|
}
|
|
}
|
|
|
|
// generateLabel returns a new label.
|
|
func (c *codegen) generateLabel(typ labelOffsetType) (uint16, string) {
|
|
name := c.nextLabel
|
|
if name == "" {
|
|
name = fmt.Sprintf("@%d", len(c.l))
|
|
}
|
|
|
|
c.nextLabel = ""
|
|
return c.newNamedLabel(typ, name), name
|
|
}
|
|
|
|
func (c *codegen) getLabelOffset(typ labelOffsetType, name string) uint16 {
|
|
return c.labels[labelWithType{name: name, typ: typ}]
|
|
}
|
|
|
|
func (c *codegen) getEqualityOpcode(expr ast.Expr) opcode.Opcode {
|
|
t, ok := c.typeInfo.Types[expr].Type.Underlying().(*types.Basic)
|
|
if ok && t.Info()&types.IsNumeric != 0 {
|
|
return opcode.NUMEQUAL
|
|
}
|
|
|
|
return opcode.EQUAL
|
|
}
|
|
|
|
// getByteArray returns byte array value from constant expr.
|
|
// Only literals are supported.
|
|
func (c *codegen) getByteArray(expr ast.Expr) []byte {
|
|
switch t := expr.(type) {
|
|
case *ast.CompositeLit:
|
|
if !isByteArray(t, c.typeInfo) {
|
|
return nil
|
|
}
|
|
buf := make([]byte, len(t.Elts))
|
|
for i := 0; i < len(t.Elts); i++ {
|
|
t := c.typeInfo.Types[t.Elts[i]]
|
|
val, _ := constant.Int64Val(t.Value)
|
|
buf[i] = byte(val)
|
|
}
|
|
return buf
|
|
case *ast.CallExpr:
|
|
if tv := c.typeInfo.Types[t.Args[0]]; tv.Value != nil {
|
|
val := constant.StringVal(tv.Value)
|
|
return []byte(val)
|
|
}
|
|
|
|
return nil
|
|
default:
|
|
return nil
|
|
}
|
|
}
|
|
|
|
func (c *codegen) convertSyscall(api, name string) {
|
|
api, ok := syscalls[api][name]
|
|
if !ok {
|
|
c.prog.Err = fmt.Errorf("unknown VM syscall api: %s", name)
|
|
return
|
|
}
|
|
emit.Syscall(c.prog.BinWriter, api)
|
|
|
|
// This NOP instruction is basically not needed, but if we do, we have a
|
|
// one to one matching avm file with neo-python which is very nice for debugging.
|
|
emit.Opcode(c.prog.BinWriter, opcode.NOP)
|
|
}
|
|
|
|
func (c *codegen) convertBuiltin(expr *ast.CallExpr) {
|
|
var name string
|
|
switch t := expr.Fun.(type) {
|
|
case *ast.Ident:
|
|
name = t.Name
|
|
case *ast.SelectorExpr:
|
|
name = t.Sel.Name
|
|
}
|
|
|
|
switch name {
|
|
case "len":
|
|
arg := expr.Args[0]
|
|
typ := c.typeInfo.Types[arg].Type
|
|
if isStringType(typ) {
|
|
emit.Opcode(c.prog.BinWriter, opcode.SIZE)
|
|
} else {
|
|
emit.Opcode(c.prog.BinWriter, opcode.ARRAYSIZE)
|
|
}
|
|
case "append":
|
|
arg := expr.Args[0]
|
|
typ := c.typeInfo.Types[arg].Type
|
|
if isByteArrayType(typ) {
|
|
emit.Opcode(c.prog.BinWriter, opcode.CAT)
|
|
} else {
|
|
emit.Opcode(c.prog.BinWriter, opcode.OVER)
|
|
emit.Opcode(c.prog.BinWriter, opcode.SWAP)
|
|
emit.Opcode(c.prog.BinWriter, opcode.APPEND)
|
|
}
|
|
case "panic":
|
|
arg := expr.Args[0]
|
|
if isExprNil(arg) {
|
|
emit.Opcode(c.prog.BinWriter, opcode.DROP)
|
|
emit.Opcode(c.prog.BinWriter, opcode.THROW)
|
|
} else if isStringType(c.typeInfo.Types[arg].Type) {
|
|
ast.Walk(c, arg)
|
|
emit.Syscall(c.prog.BinWriter, "Neo.Runtime.Log")
|
|
emit.Opcode(c.prog.BinWriter, opcode.THROW)
|
|
} else {
|
|
c.prog.Err = errors.New("panic should have string or nil argument")
|
|
}
|
|
case "SHA256":
|
|
emit.Opcode(c.prog.BinWriter, opcode.SHA256)
|
|
case "SHA1":
|
|
emit.Opcode(c.prog.BinWriter, opcode.SHA1)
|
|
case "Hash256":
|
|
emit.Opcode(c.prog.BinWriter, opcode.HASH256)
|
|
case "Hash160":
|
|
emit.Opcode(c.prog.BinWriter, opcode.HASH160)
|
|
case "VerifySignature":
|
|
emit.Opcode(c.prog.BinWriter, opcode.VERIFY)
|
|
case "AppCall":
|
|
numArgs := len(expr.Args) - 1
|
|
c.emitReverse(numArgs)
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.APPCALL)
|
|
buf := c.getByteArray(expr.Args[0])
|
|
if len(buf) != 20 {
|
|
c.prog.Err = errors.New("invalid script hash")
|
|
}
|
|
|
|
c.prog.WriteBytes(buf)
|
|
case "Equals":
|
|
emit.Opcode(c.prog.BinWriter, opcode.EQUAL)
|
|
case "FromAddress":
|
|
// We can be sure that this is a ast.BasicLit just containing a simple
|
|
// address string. Note that the string returned from calling Value will
|
|
// contain double quotes that need to be stripped.
|
|
addressStr := expr.Args[0].(*ast.BasicLit).Value
|
|
addressStr = strings.Replace(addressStr, "\"", "", 2)
|
|
uint160, err := address.StringToUint160(addressStr)
|
|
if err != nil {
|
|
c.prog.Err = err
|
|
return
|
|
}
|
|
bytes := uint160.BytesBE()
|
|
emit.Bytes(c.prog.BinWriter, bytes)
|
|
}
|
|
}
|
|
|
|
// transformArgs returns a list of function arguments
|
|
// which should be put on stack.
|
|
// There are special cases for builtins:
|
|
// 1. When using AppCall, script hash is a part of the instruction so
|
|
// it should be emitted after APPCALL.
|
|
// 2. With FromAddress, parameter conversion is happening at compile-time
|
|
// so there is no need to push parameters on stack and perform an actual call
|
|
// 3. With panic, generated code depends on if argument was nil or a string so
|
|
// it should be handled accordingly.
|
|
func transformArgs(fun ast.Expr, args []ast.Expr) []ast.Expr {
|
|
switch f := fun.(type) {
|
|
case *ast.SelectorExpr:
|
|
if f.Sel.Name == "AppCall" || f.Sel.Name == "FromAddress" {
|
|
return args[1:]
|
|
}
|
|
case *ast.Ident:
|
|
if f.Name == "panic" {
|
|
return args[1:]
|
|
}
|
|
}
|
|
|
|
return args
|
|
}
|
|
|
|
func (c *codegen) convertByteArray(lit *ast.CompositeLit) {
|
|
buf := make([]byte, len(lit.Elts))
|
|
for i := 0; i < len(lit.Elts); i++ {
|
|
t := c.typeInfo.Types[lit.Elts[i]]
|
|
val, _ := constant.Int64Val(t.Value)
|
|
buf[i] = byte(val)
|
|
}
|
|
emit.Bytes(c.prog.BinWriter, buf)
|
|
}
|
|
|
|
func (c *codegen) convertMap(lit *ast.CompositeLit) {
|
|
emit.Opcode(c.prog.BinWriter, opcode.NEWMAP)
|
|
for i := range lit.Elts {
|
|
elem := lit.Elts[i].(*ast.KeyValueExpr)
|
|
emit.Opcode(c.prog.BinWriter, opcode.DUP)
|
|
ast.Walk(c, elem.Key)
|
|
ast.Walk(c, elem.Value)
|
|
emit.Opcode(c.prog.BinWriter, opcode.SETITEM)
|
|
}
|
|
}
|
|
|
|
func (c *codegen) convertStruct(lit *ast.CompositeLit) {
|
|
// Create a new structScope to initialize and store
|
|
// the positions of its variables.
|
|
strct, ok := c.typeInfo.TypeOf(lit).Underlying().(*types.Struct)
|
|
if !ok {
|
|
c.prog.Err = fmt.Errorf("the given literal is not of type struct: %v", lit)
|
|
return
|
|
}
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.NOP)
|
|
emit.Int(c.prog.BinWriter, int64(strct.NumFields()))
|
|
emit.Opcode(c.prog.BinWriter, opcode.NEWSTRUCT)
|
|
|
|
// We need to locally store all the fields, even if they are not initialized.
|
|
// We will initialize all fields to their "zero" value.
|
|
for i := 0; i < strct.NumFields(); i++ {
|
|
sField := strct.Field(i)
|
|
fieldAdded := false
|
|
|
|
// Fields initialized by the program.
|
|
for _, field := range lit.Elts {
|
|
f := field.(*ast.KeyValueExpr)
|
|
fieldName := f.Key.(*ast.Ident).Name
|
|
|
|
if sField.Name() == fieldName {
|
|
emit.Opcode(c.prog.BinWriter, opcode.DUP)
|
|
|
|
pos := indexOfStruct(strct, fieldName)
|
|
emit.Int(c.prog.BinWriter, int64(pos))
|
|
|
|
ast.Walk(c, f.Value)
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.SETITEM)
|
|
fieldAdded = true
|
|
break
|
|
}
|
|
}
|
|
if fieldAdded {
|
|
continue
|
|
}
|
|
|
|
typeAndVal, err := typeAndValueForField(sField)
|
|
if err != nil {
|
|
c.prog.Err = err
|
|
return
|
|
}
|
|
|
|
emit.Opcode(c.prog.BinWriter, opcode.DUP)
|
|
emit.Int(c.prog.BinWriter, int64(i))
|
|
c.emitLoadConst(typeAndVal)
|
|
emit.Opcode(c.prog.BinWriter, opcode.SETITEM)
|
|
}
|
|
}
|
|
|
|
func (c *codegen) convertToken(tok token.Token) {
|
|
switch tok {
|
|
case token.ADD_ASSIGN:
|
|
emit.Opcode(c.prog.BinWriter, opcode.ADD)
|
|
case token.SUB_ASSIGN:
|
|
emit.Opcode(c.prog.BinWriter, opcode.SUB)
|
|
case token.MUL_ASSIGN:
|
|
emit.Opcode(c.prog.BinWriter, opcode.MUL)
|
|
case token.QUO_ASSIGN:
|
|
emit.Opcode(c.prog.BinWriter, opcode.DIV)
|
|
case token.REM_ASSIGN:
|
|
emit.Opcode(c.prog.BinWriter, opcode.MOD)
|
|
case token.ADD:
|
|
emit.Opcode(c.prog.BinWriter, opcode.ADD)
|
|
case token.SUB:
|
|
emit.Opcode(c.prog.BinWriter, opcode.SUB)
|
|
case token.MUL:
|
|
emit.Opcode(c.prog.BinWriter, opcode.MUL)
|
|
case token.QUO:
|
|
emit.Opcode(c.prog.BinWriter, opcode.DIV)
|
|
case token.REM:
|
|
emit.Opcode(c.prog.BinWriter, opcode.MOD)
|
|
case token.LSS:
|
|
emit.Opcode(c.prog.BinWriter, opcode.LT)
|
|
case token.LEQ:
|
|
emit.Opcode(c.prog.BinWriter, opcode.LTE)
|
|
case token.GTR:
|
|
emit.Opcode(c.prog.BinWriter, opcode.GT)
|
|
case token.GEQ:
|
|
emit.Opcode(c.prog.BinWriter, opcode.GTE)
|
|
case token.EQL:
|
|
emit.Opcode(c.prog.BinWriter, opcode.NUMEQUAL)
|
|
case token.NEQ:
|
|
emit.Opcode(c.prog.BinWriter, opcode.NUMNOTEQUAL)
|
|
case token.DEC:
|
|
emit.Opcode(c.prog.BinWriter, opcode.DEC)
|
|
case token.INC:
|
|
emit.Opcode(c.prog.BinWriter, opcode.INC)
|
|
case token.NOT:
|
|
emit.Opcode(c.prog.BinWriter, opcode.NOT)
|
|
case token.AND:
|
|
emit.Opcode(c.prog.BinWriter, opcode.AND)
|
|
case token.OR:
|
|
emit.Opcode(c.prog.BinWriter, opcode.OR)
|
|
case token.SHL:
|
|
emit.Opcode(c.prog.BinWriter, opcode.SHL)
|
|
case token.SHR:
|
|
emit.Opcode(c.prog.BinWriter, opcode.SHR)
|
|
case token.XOR:
|
|
emit.Opcode(c.prog.BinWriter, opcode.XOR)
|
|
default:
|
|
c.prog.Err = fmt.Errorf("compiler could not convert token: %s", tok)
|
|
return
|
|
}
|
|
}
|
|
|
|
func (c *codegen) newFunc(decl *ast.FuncDecl) *funcScope {
|
|
f := newFuncScope(decl, c.newLabel())
|
|
c.funcs[f.name] = f
|
|
return f
|
|
}
|
|
|
|
// CodeGen compiles the program to bytecode.
|
|
func CodeGen(info *buildInfo) ([]byte, error) {
|
|
pkg := info.program.Package(info.initialPackage)
|
|
c := &codegen{
|
|
buildInfo: info,
|
|
prog: io.NewBufBinWriter(),
|
|
l: []int{},
|
|
funcs: map[string]*funcScope{},
|
|
labels: map[labelWithType]uint16{},
|
|
typeInfo: &pkg.Info,
|
|
}
|
|
|
|
// Resolve the entrypoint of the program.
|
|
main, mainFile := resolveEntryPoint(mainIdent, pkg)
|
|
if main == nil {
|
|
c.prog.Err = fmt.Errorf("could not find func main. Did you forget to declare it? ")
|
|
return []byte{}, c.prog.Err
|
|
}
|
|
|
|
funUsage := analyzeFuncUsage(info.program.AllPackages)
|
|
|
|
// Bring all imported functions into scope.
|
|
for _, pkg := range info.program.AllPackages {
|
|
for _, f := range pkg.Files {
|
|
c.resolveFuncDecls(f)
|
|
}
|
|
}
|
|
|
|
// convert the entry point first.
|
|
c.convertFuncDecl(mainFile, main)
|
|
|
|
// sort map keys to generate code deterministically.
|
|
keys := make([]*types.Package, 0, len(info.program.AllPackages))
|
|
for p := range info.program.AllPackages {
|
|
keys = append(keys, p)
|
|
}
|
|
sort.Slice(keys, func(i, j int) bool { return keys[i].Path() < keys[j].Path() })
|
|
|
|
// Generate the code for the program.
|
|
for _, k := range keys {
|
|
pkg := info.program.AllPackages[k]
|
|
c.typeInfo = &pkg.Info
|
|
|
|
for _, f := range pkg.Files {
|
|
for _, decl := range f.Decls {
|
|
switch n := decl.(type) {
|
|
case *ast.FuncDecl:
|
|
// Don't convert the function if it's not used. This will save a lot
|
|
// of bytecode space.
|
|
if n.Name.Name != mainIdent && funUsage.funcUsed(n.Name.Name) {
|
|
c.convertFuncDecl(f, n)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if c.prog.Err != nil {
|
|
return nil, c.prog.Err
|
|
}
|
|
buf := c.prog.Bytes()
|
|
if err := c.writeJumps(buf); err != nil {
|
|
return nil, err
|
|
}
|
|
return buf, nil
|
|
}
|
|
|
|
func (c *codegen) resolveFuncDecls(f *ast.File) {
|
|
for _, decl := range f.Decls {
|
|
switch n := decl.(type) {
|
|
case *ast.FuncDecl:
|
|
if n.Name.Name != mainIdent {
|
|
c.newFunc(n)
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *codegen) writeJumps(b []byte) error {
|
|
ctx := vm.NewContext(b)
|
|
for op, _, err := ctx.Next(); err == nil && ctx.NextIP() < len(b); op, _, err = ctx.Next() {
|
|
switch op {
|
|
case opcode.JMP, opcode.JMPIFNOT, opcode.JMPIF, opcode.CALL:
|
|
// we can't use arg returned by ctx.Next() because it is copied
|
|
nextIP := ctx.NextIP()
|
|
arg := b[nextIP-2:]
|
|
|
|
index := binary.LittleEndian.Uint16(arg)
|
|
if int(index) > len(c.l) {
|
|
return fmt.Errorf("unexpected label number: %d (max %d)", index, len(c.l))
|
|
}
|
|
offset := c.l[index] - nextIP + 3
|
|
if offset > math.MaxUint16 {
|
|
return fmt.Errorf("label offset is too big at the instruction %d: %d (max %d)",
|
|
nextIP-3, offset, math.MaxUint16)
|
|
}
|
|
binary.LittleEndian.PutUint16(arg, uint16(offset))
|
|
}
|
|
}
|
|
return nil
|
|
}
|